The present invention relates to optical films and optical displays incorporating the optical films. In particular, the present invention relates to a multilayer optical assembly comprising a reflective polarizing layer attached to a light diffusing layer with voids defined in an intermediate region therebetween.
Optical displays, such as liquid crystal displays (LCDs), are becoming increasingly commonplace, finding use for example in mobile telephones, in hand-held computer devices such as personal digital assistants (PDAs) and electronic games, and in larger devices such as laptop computers, LCD monitors, and LCD television screens. The incorporation of light management films into optical display devices results in improved display performance. Different types of films, including prismatically structured films, reflective polarizers, and diffuser films are useful for improving display parameters such as output luminance, luminance uniformity, viewing angle, and overall system efficiency. Such improved operating characteristics make devices easier to use and may also increase battery life.
Light management films incorporated into optical displays are typically stacked, one by one, into the display frame between a light source and a light gating device. The stack of films can be optimized to obtain a particular desired optical performance. From a manufacturing perspective, however, several issues can arise from the handling and assembly of several discrete film pieces. These problems include the excess time required to remove protective liners from individual optical films, along with the increased chance of damaging a film when removing a liner. In addition, the insertion of multiple individual sheets into the display frame is time consuming and the stacking of individual films provides further opportunity for the films to be damaged. All of these problems can contribute to diminished overall throughput or to reduced yield, which leads to higher system cost.